Complete Sequence of the New Lactococcal Abortive Phage Resistance Gene abiO

Prevots, Fabien; Ritzenthaler, Paul

doi:10.3168/jds.s0022-0302(98)75713-3

Cited by 20 publications

(6 citation statements)

References 20 publications

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“…This range of efficacy against the three main phage groups has been observed with other lactococcal Abi mechanisms (4,14,26,53,65,66), but the lack of similarity with other Abi proteins suggests that there is a different mode of action. Combinations of diverse phage resistance mechanisms are often observed for plasmids isolated from wild-type strains of L. lactis that are highly resistant to phages (2,21,25,32).…”

Section: Discussionmentioning

confidence: 85%

AbiV, a Novel Antiphage Abortive Infection Mechanism on the Chromosome of Lactococcus lactis subsp. cremoris MG1363

Haaber

Moineau

Fortier

et al. 2008

Appl Environ Microbiol

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Insertional mutagenesis with pGhost9::ISS1 resulted in independent insertions in a 350-bp region of the chromosome of Lactococcus lactis subsp. cremoris MG1363 that conferred phage resistance to the integrants. The orientation and location of the insertions suggested that the phage resistance phenotype was caused by a chromosomal gene turned on by a promoter from the inserted construct. Reverse transcription-PCR analysis confirmed that there were higher levels of transcription of a downstream open reading frame (ORF) in the phage-resistant integrants than in the phage-sensitive strain L. lactis MG1363. This gene was also found to confer phage resistance to L. lactis MG1363 when it was cloned into an expression vector. A subsequent frameshift mutation in the ORF completely eliminated the phage resistance phenotype, confirming that the ORF was necessary for phage resistance. This ORF provided resistance against virulent lactococcal phages belonging to the 936 and c2 species with an efficiency of plaquing of 10 ؊4 , but it did not protect against members of the P335 species. A high level of expression of the ORF did not affect the cellular growth rate. Assays for phage adsorption, DNA ejection, restriction/modification activity, plaque size, phage DNA replication, and cell survival showed that the ORF encoded an abortive infection (Abi) mechanism. Sequence analysis revealed a deduced protein consisting of 201 amino acids which, in its native state, probably forms a dimer in the cytosol. Similarity searches revealed no homology to other phage resistance mechanisms, and thus, this novel Abi mechanism was designated AbiV. The mode of action of AbiV is unknown, but the activity of AbiV prevented cleavage of the replicated phage DNA of 936-like phages.

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Section: Discussionmentioning

confidence: 85%

AbiV, a Novel Antiphage Abortive Infection Mechanism on the Chromosome of Lactococcus lactis subsp. cremoris MG1363

Haaber

Moineau

Fortier

et al. 2008

Appl Environ Microbiol

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“…In addition, AbiU consists of abiU1 and abiU2 (40) and some Abis exhibit toxicity (i.e. AbiB (4), AbiD1 (41,42), AbiK (43), AbiN (44), AbiO (45), AbiQ (9,12) and AbiRa-c (46)). Theoretically, these Abis might have RNA antitoxins (i.e.…”

Section: Resultsmentioning

confidence: 99%

A widespread bacteriophage abortive infection system functions through a Type IV toxin–antitoxin mechanism

Przybilski

Semeijn

et al. 2014

Nucleic Acids Research

252

237

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Bacterial abortive infection (Abi) systems are ‘altruistic’ cell death systems that are activated by phage infection and limit viral replication, thereby providing protection to the bacterial population. Here, we have used a novel approach of screening Abi systems as a tool to identify and characterize toxin–antitoxin (TA)-acting Abi systems. We show that AbiE systems are encoded by bicistronic operons and function via a non-interacting (Type IV) bacteriostatic TA mechanism. The abiE operon was negatively autoregulated by the antitoxin, AbiEi, a member of a widespread family of putative transcriptional regulators. AbiEi has an N-terminal winged-helix-turn-helix domain that is required for repression of abiE transcription, and an uncharacterized bi-functional C-terminal domain, which is necessary for transcriptional repression and sufficient for toxin neutralization. The cognate toxin, AbiEii, is a predicted nucleotidyltransferase (NTase) and member of the DNA polymerase β family. AbiEii specifically bound GTP, and mutations in conserved NTase motifs (I-III) and a newly identified motif (IV), abolished GTP binding and subsequent toxicity. The AbiE systems can provide phage resistance and enable stabilization of mobile genetic elements, such as plasmids. Our study reveals molecular insights into the regulation and function of the widespread bi-functional AbiE Abi-TA systems and the biochemical properties of both toxin and antitoxin proteins.

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“…Abi-mediated resistance typically culminates in the death of the infected host cell in order to limit the release of progeny particles, thus protecting the neighbouring bacterial population. Currently, 23 Abi systems (AbiA-AbiZ) are known for L. lactis , which, with the exception of AbiN and AbiV, are all plasmid-encoded (Prevots and Ritzenthaler 1998 ; Chopin et al 2005 ; Ainsworth et al 2014a , c ). The presence of Abi systems was first identified due to the protective effect that certain lactococcal plasmids have against phage infection, by causing a decreased burst size and an altered phage plaque morphology as observed for plasmids pTR2030 and pIL105 (Sing and Klaenhammer 1986 ; Gautier and Chopin 1987 ).…”

Section: Next-generation Sequencing (Ngs) Approachesmentioning

confidence: 99%

Next-generation sequencing as an approach to dairy starter selection

Kelleher

Murphy

Mahony

et al. 2015

Dairy Sci. & Technol.

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Lactococcal and streptococcal starter strains are crucial ingredients to manufacture fermented dairy products. As commercial starter culture suppliers and dairy producers attempt to overcome issues of phage sensitivity and develop new product ranges, there is an ever increasing need to improve technologies for the rational selection of novel starter culture blends. Whole genome sequencing, spurred on by recent advances in next-generation sequencing platforms, is a promising approach to facilitate rapid identification and selection of such strains based on gene-trait matching. This review provides a comprehensive overview of the available methodologies to analyse the technological potential of candidate starter strains and highlights recent advances in the area of dairy starter genomics.

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Complete Sequence of the New Lactococcal Abortive Phage Resistance Gene abiO

Cited by 20 publications

References 20 publications

AbiV, a Novel Antiphage Abortive Infection Mechanism on the Chromosome of Lactococcus lactis subsp. cremoris MG1363

AbiV, a Novel Antiphage Abortive Infection Mechanism on the Chromosome of Lactococcus lactis subsp. cremoris MG1363

A widespread bacteriophage abortive infection system functions through a Type IV toxin–antitoxin mechanism

Next-generation sequencing as an approach to dairy starter selection

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